The Sage of Omaha is at it again. On Thursday afternoon, Warren Buffett's investment vehicle Berkshire Hathaway increased its stake in supermarket giant Tesco from 3.21% to 5.08%.

Buffett was quoted as saying, only in November, that he would buy more Tesco shares if the price came down. Lo and beyond, one profit warning and a sales slide later, and Tesco shares hit a 34-month low of 311p on Monday.

The move by Buffett, one of world's top three richest people, is a resounding vote of confidence in the global brand, which has felt the pressure of reduced consumer spending in recent months. Sales in the third quarter declined by 0.3% and analysts predict a tough year ahead for Tesco. But Buffett's not known as the 'Sage' for nothing.

If he's invested £350m of his own cash into Tesco just days after £6bn is wiped off its share price, he must see a pretty impressive turnaround on the cards.

And Buffett is extremely au fait with Tesco's business model. Last year, he called the supermarket's attempt to enter the US grocery market with its Fresh & Easy chain 'foohardy'. He was right. The business has been loss-making since inception, and many stores have now been mothballed.

Expect a massive surge in Tesco shares as mini-Buffetts seek to replicate his stock gamble. Well, he has amassed a $50bn fortune off the back of his calculated punts...